Factors related to bone mineral density in calcaneus of young women -specifically focused on its relationship with physical activity-

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09670388
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Public health/Health science
• Research Institution: Tottori University
• Principal Investigator: OHSHIRO Hitoshi Tottori University faculty of Medicine Department of Public Health, Associate Professor, 医学部, 助教授 (40160486)
• Co-Investigator(Kenkyū-buntansha): KAMEZAKI Sachiko Tottori Women's college, Associate Professor, 助教授 (00177601) ; KUROZAWA Youichi Tottori University faculty of Medicine Department of Public Health, Instructor, 医学部, 助手 (50161790)
• Project Period (FY): 1997 – 1998
• Keywords: BONE MINERAL DENSITY / PHYSICAL EXERCISE / OSTEOPOROSIS / PREVENTION / PEAK BONE MASS / NUTRITION

Research Abstract

Material and method : We carried out both cross-sectional and longitudinal studies to identify lifestyle factors which relate to bone mineral density (BMD) in young females. A total of 129 and 66 female college students were enrolled in the studies respectively. In both studies, their calcaneal bone mineral density, habitual exercise and dietary calcium intake were measured. In the longitudinal study, the same measurements were conducted one year after with a questionnaire about the change of dietary habits and physical activity.
Results : In the cross-sectional study, current physical activity and body weight were correlated with BMI) in multiple regression analysis. There was no significant relationship between calcium intake and BMD.Students who played tennis, volleyball or basketball showed higher BMD than students who did not join any athletic dubs. In the longitudinal study, average BMD decreased 9.4mg/cm_2 during a one year period. The BMD difference between the two measurements were associated with the BMD measured one year after, physical activity during winter season, and the regularity of having meals. Although their body weight was in the normal range, students who tried to go on a diet decreased their BMD more than those who did not attempt to diet (-16.9mg/cm_2 v.s. -7.3mg/cm_2), but it was not significant (P=0.06). During the one year follow-up, 17 students continued habitual exercises for more than 6 months and decreased -1.9mg/cm_2 in BMD while the other 49 students who had exercised less decreased -12.0mg/cm_2. This difference was statistically significant (P<0.001).
Conclusion : We concluded that regular physical activity, adequate body weight and healthy dietary habits were essential for young females to maintain calcaneal BMD and might prevent future osteoporosis.